officials tell nbc news that the two suspects are residents of the united states. communities and colleges around the boston area on lockdown. in fact, now, the entire city of boston, as we just learned at a press conference a few moments ago. a shelter in place order which means, in effect, stay where you are and lock the doors for the entire city of boston. all told, almost 1 million people being asked to stay inside their homes with their doors locked. >> this area is literally being put into a grinding halt. when you think about this from 20,000 feet or on a national scope. mass transit is shut down. all of mbta, amtrak from providence to boston is shut down, as well. even some low-level air space above boston is closed. as willie mentioned, everything is coming to a halt. m.i.t., emerson, boston college, umass, boston, berkeley, tufts, suffolk university, all closed today. no classes. >> mike barnicle, this is terrorism defined. you have 1 million people inside with the doors locked wondering if a suspect who was willing to take lives and take his own life is